Process of detinning.



ELMER A. 'SPERRY, OF BROOKLYN, NEW YORK.

rnocnss or nnrmn'mc.

T 0 all whom it may concern:

Be it known that I, ELMER A. SPERRY, a citizen of the United States,residing at Brooklyn, in the county of Kings'and State of New York, haveinvented new and useful Im rovements in Processes of Detinning, of

.wluch the following is a specification.

My invention relates to de-tinning and consists of a process whereby tinscrap 1 or other tin bearing material may be treated in an economicaland commercial method and one adapted to the conditions which exist inhandling large masses of material from which on? small recoveries are tobe expected.

t'further consists in steps of the process which guard against thelosses of values which are thus reclaimed and by means of which thesevalues are converted into commercial and marketable form.

It has long been known that a dry method of de-tinning would possessadvantages overv the wet process; the great bulk of the material to ehandled together with the ex tremely large surface exposed, togetherwith the small percentage of tin. present, also the necessity of freedomfrom rust of the sheet steel remaining, all point to the desirability.of a dry over a wet method. Attempts have been made and suggestions havebeen put forward, but none of these processes appear to have beenadopted.- The reason is not far to seek. When chlorin is used as thedetinning agent the almost absolute dryness necessary to be attained andalso maintained throughout, not only with the incoming gas but with eachfresh addition of tinned material or scrap itself: furthermore, thenecessity of eliminating other active gases and also the necessity ofpreventing the forma tion of ferric chlorid which in presence ofmoisture breaks up into hydrochloric acid and iron oxid and thusattacking further masses of the steel, all pointto the necessit Tofseeking .a method that will at once elim1- nate the difficultiesointed out and efiectually prevent the mu tiplication of secondaryreactions which decrease the efliciency and destroys the value of thesteel scrap. This scrap to be commercial should be thoroughly free fromforeign metals, these elements re; maining below .04 per cent. and thescrap which remains should be free from rust.

Chlorin gas' as most abundantly produced is usually adulterated withair, CO and also Specification of Letters latent.

Application filed April 13. 1906- Serial No. 311.560-

Patentad Dec. 10 1907.

carries moisture.

in the commercial reclaiming The problem kept in view: in the presentprocess is to utilize such a gasv of both the tin and the steel from tinscra which may be considered as the principal ormofraw material. Inseeking the solution of this prob.-

lem I have at last found a gaseous substance which when associated withchlorin renders profitable. f

the process both workableand I The present specification sets forth both.the detai s and process of de-tinning based on my discovery and statesthe adjustment of conditions imposed in commercial adaptation thereofand also illustration one metho ess into effect.

My invention consists in subjecting the oints out by wayof (l ofcarrying the procmaterial to bade-tinned to various steps in a processincluding treating with gaseous mlxture under certain specifiedconditions of temperature control and also control ofthe' ingredientsof-such mixture which I have discovered to be effective in the completeremoval of the tin and also leavi the scrap in the best possiblecondition for t e market.

I have discovered that a mixture of ous stannic chlorid stannic chlorid,with fold conditions imposed in a successful com mercial process morecom letely than any compound I have used. true considering the fact thatchlorin as at specially is this" present produced is associated withmore or less abundant mixture of an, other gasesand mo1stur'e, as abovestated. Moreover it is very difficult not only to dry the gas but tokeep it dry during the progress of the process. Any moisture containedin the gases or the tin bearing ,rnaterial, suchffor in-y stance, asmetal cuttings or scrap causes attack upon the steel. attack isprevented by the presence of the I have found that, this chlorid, thisbeing one of the manifold func? tions performed by its presence. Theinven-e tion also includes such stepsas the freeing of the material ofthe last trace of chlorid or which are pointed out toillustratethistreatment.

forms, for instance that which-con'stit11tes the largest ofall knownsupplies';namely the gases arising from an electrolytic plant "for 8particularly anhy rous chlorin fulfils the man -v:

10ochlorid hydrate by suitable means some of I wus'ually consistofchloriri, air and some 00,,

decomposition of common saltg. these gases all saturated ,with moistureat the temperature. These are first chilled or refrigerated to throw outall the moisture possible in this manner and then treated. withanhydrous stannic' chlorid either as a liquid or a vapor or steam, thelatter being preferred. The gas is preferably heated at'thispoint thoughthis may not-in some cases be necessary. Any desired amount of chloridmayjthus be associated with the gaseous chlorin and accompanying gasesto or even beyond the point I ofsaturation of the gases with thechlorid. If,

however, toomuch chlorid is found to be taken up or to" be entrainedwith the gases, a

part may be thrown out by chilling to a more or less degree,,thus givingan easy method of gaging the chlorid content. The chlorid thus condensedmay be returned to the liquid in the drying-or treating vessel or to the'boiler for the chlorid which produces the steam or vapor for a thetreatment, .When

gaseous chlorin, either diluted. or otherwise,

is thus refrigerated to throw out all the moisture possible as statedabove, thegas may be rendered anhydrous as chlorin anhydri'd is formedlocking up, so to speak,

and thus eliminating such moisture as remains 'p sfl t at thetemperature in thechlorin'and also the other gases if any are stillfurther cooled and even liquefied, but'as present. I If desired thechlorin'may-t'hen be is well known, .upon again bein warmed it her.

expands as a-gas to its origina or' even a .greater volume, depending.of course upon 1 the final temperature.

The material'to be treated is placed a There may be a lurality of suchvessels which are prefera ly coupledin series by conduits which arecovered or otherwise organized to prevent escape of heat of the ases asthey, pass from one treating chamer to another, and the conduits alsoinclude 'acondenser which thegases are compelled to 'traverseand whereinsome of the chlorids of are condensed and recovered. These condensersare provided with suitable cooling means which as in the case of, thefirst one mentioned are governed in such way as to remove anypredetermined portion or percentage of the chloridcontent. As the gasesthat have been refrigerated, or otherwise treated for eliminating themoisture, are ex- ,treatin'g. chamber as. desired.

panded and admitted in the gaseous state to the reaction chamber, thetin upon the scrap orother tin bearing material which, while it remainsin the process, I denom'inate raw material, is' very quickly convertedinto chlorid. The gas may take up suchchloridin; whole or part andcarryit along as vapor;

the remaining .chlorid' isdrawn from the 4 The gases may absorb thevapors to the'point of saturation. some in'addition may also beentrained therewith so that the gases are found to be associated withmore chlorid than is necessary for carrying on the rocess in thesuccessive chambers when t ese are employed. The excess of chlorid isremoved by the. condensers as described in connection with that firstmentioned, this being accomplished between the chambers as explained. Itwill be understood that the gaseous mixture contains an amountof.stannic chlor'id hydrate. This is an active agent in de-tinning as ittakes up tin to form stannous chloridwhich quickly is transformed intostannic chloridjthrough the [action of'the' chlorin present. The hydratealso is an active carrier of chlorin to tin as has been reviously'-pointed out-by 'me in this art. he important function of the anhydrouscontentof the/gas is'self'evident as it stands ready. to

take u any water or moistureintroduced,

opene up or developed in the scrap or gases during the treatment, alsosuch moisture as may accumulate on thewalls of the chambers standingopen during the process of re-charging. For-somepurposes. the vesselsmay be connected in rotation. Here'a plurality of treating chambers areso coupled, for ins stance in a circle or. endless series, so that thereagent. canbe introduced and removed at any point; that is, any chambermay become the first in the seriesand any one the last in the series,the arrangement being such as usually to leave one or more chambersbetween the first and the last which are idle and from which thematerials are being either introduced or withdrawn. Considering anyarran ement that will harmonize with this general i ea, it will readilybe understood that the condenser attached to the idle chambers will alsobe outof circuit and idle. The gases after having passed through theseries of .vessels and their interspersed condensers, and having alsopassed the condenser attached to the vessel, which for the time being islast in the" series, the residuary gases are conducted into a tower,scrubber or.

equivalent device and are there treated with a solvent not only for thestannic chlorid content ofthe gases but also such as will actto absorb-or dissolve any. remaining chlorin as well. Stannous chlorid and waterare substances which may be cited as 'fulfiling this specification. 'Intreating relative, temperatures' hereinpI prefer to state same in lterms of congealing points rather than the melting points of thehydrated stannic chlorid as the congealing oints seem to be much moreuniform than t is apparent melting points for the various hydrates orhydrates with various waters of hydration.

The gases on their way to the tower are Insulated against loss of heator jacketed to 'prevent loss of heat or supplied with sufficlient heatto prevent them from condensing and stopping. the passages. To furtherillustrate one method of procedure, it will be interesting to note thatthe progression of the gases through the series is preferably back- 1ward-that is, backwardly with reference to the progression of the seriesitself; the gases entering on the vessel which has been longest intreatment and leaving by the vessel which is freshly charged with scrapor tin bearin material. By this means the exhauste gases are broughtinto contact with the fresh temperature of each chamber is adjusted tobest suit the necessity'ofthe case, and also for best degree ofpenetration into the re cessesof the more or less tightly packedportions of the scrap. Generally speaking,

owever, the temperature of the series is preferably controlled so thatthe temperature may eration of any given mass of scrap proceeds. Tofurther illustrate one method of procedure; a body of scrap or rawmaterial,

'its chamber and connected condenser which 40 is the next one -to betaken out of series and when so taken out is first exhausted and thegases returned to the system; next the connection with the system isbroken and this chamber is connected direct to the tower and the furtherexhaustion of the chamber is led {directly thereto so that .the valuesmay be dissolved as above described} During this exhaustion in someinstan-cesfit is found best to elevate the temperature above that usedin the normal operation, which is also true in the next step where thetemperature may be forced still hi her to aid in the removal ofanystannic chlorid hydrate which may have crystallized upon the surface ofthe scrap during this step or after. Preferably the farthest pointremoved from the suction is then opened to the air and the exhaustionproceeds accompanied by the inrush of air or mert gas, preferably driedand heated air,

by means of which the remaining material or black scrap is freed fromthe last vestage of the remaining chlorid in any manner best suited tothe purpose. After these are thoroughly ljremoved the chamber is openedbe gradually increased as the optinned material.

up, scrap removed. and fresh supply introduced. Thereupon the "chamber'is then cl'osed and the mass is ready for the next shift in theprogression of the series. In some instances the scrap is then washedfree and clarified from the vapors which'it may still contain aftercooling.

The order of the steps and their detail may be varied and some may beused without the others and the invention extends to such use.

I claim 1. The method of de-tinning which consists in subjecting the rawmaterial to the gaseous gaseous stanm'c chlorid and'chlorin.

4. The method of de-tinning which consists in subjecting the rawmaterial to the 'persistent action of a mixture of gaseous stannicchlorid and chlorin at a temperatureabove the congealing point ofstanm'c chlorid hydrate.

5. The method of de-tinning which consists in subjecting the rawmaterial to the persistent action of a mixture of gaseous stannicchlorid and chlorin and controlling the temperature.

6. The method of de-tinning which consists in subjecting the rawmaterial while in a dry heated state to the persistent action of amixture of gaseous stannic chlorid and chlorin.

7 The method of de-tinning which consists in re-acting upon dry materialto be detinned with a mixture of gaseous stannic chlorid and chlorin andgradually increasing the temperature of the re-acting mass as theprocess goes forward.

8. The method of de-tinning which consists in first treating chlorinwith stannic chlorid and re-acting with chlorin thus treated upon a bodyof tinned material.

9. The method of de-tinning which consists in treating chlorin withstannic chlorid vapors at an elevated temperature and cooling the mixedgases thus produced and reacting with chlorin thus treated upon the 10.The method of de-tinning which consists in first treating chlorin gasand air with stannic chlorid and re-acting with chlorin thus treatedupon a body of tinned material.

11. The method of de-tinning which consists in re-acting upon drymaterial to be detinned with a mixture of gases containing chlorin-andafterward heating the metal and treating same with air. 1

12., The method of de-tinning which conchlorin and afterward heating themetal and treating same with heated air.

13. The method of de-tinning which consists in treating separate butconnected bodies of timied'material with a mixture of gaseousstannicchlorid and .chlorin and removing stannic chlorid from thetreating fluid intermediate between each of suchbodies. v g

14. The method of de-tinning which consists in treating separate butconnected bodies of tinned material with a mixture of gaseous stannicchlorid andchlorin and removing chlorinated stannic chlorid content ofthe treating fluid intermediate between such bodies.

15. The method of de-tinning which ,consists in treating separate butconnect-ed bodies of tinned material with a mixture of v gaseous stannicchlorid and chlorin and successively removing the chlorid from thetreating gas by changing the temperature oi.

' such gases.

16.' The method of de-tinning which consists in treating separate butconnected sists in successively treating separate bodies 0t tinnedmaterial with a mixture of gaseous stannic chloridandchlorin andsuccessively removing the chlorid from the treating gas and bringing theterminal gases intocontact with a solvent for stannic chiorid andchlorin.

18. The method of de tinning whiclrcona sists in re-acting upon thematerial to be de tinned in its dry state with gaseous chlorin whichconsists in refrigerating such chlorin, treating it with a drying agent,then cooling the gas to expel excess of the drying agent and bringingthechlorin together with the drying agent in gaseous torm into the reaction chamber.

19. T he method of de-tinning which con sists in the persistent reactionupon the material to be de-tinned in its dry condition of a mixture ofgaseous stannrcchlond and chlorin which has been cooled to avoid excessof stannic chiorid. p

20. The method of de-tinning which consists in re-acting upon thematerial to be detinned in its dry stat-e'with'a mixture of air,

ehlorin and water vapor, all of which have been heated, treated withstannic chiorid and-afterward chilled. 1

21. A method of de-t' erases sists in subf'ecting a plurality of bodiesof raw materia to the persistent action of gaseous stannic chlorid andchlorin, disconnecting one of such bodies, removing the gases therefromand returning the same to the process.

The method of de-t-inning which con-.- sists in treating separate bodiesof tinned material with aseous 'chlorin, disconnecting one of suchbodies, removing the gases therefrom and returning same to therocessland then drawing air through such ody and a solvent for stannicichlorid.

23. The method of de-tinning which consists in treating separate bodiesof tinned material with aseous chlorin, disconnecting one of suchbodies, removing the gases therefrom and returning same to the processand thenrdrawing air through such body while, at an elevatedtemperature.

24. The method of de-tmning which consists in subi'ecting a plurality ofbodies of raw materia to the persistent action'of'ga'seous stannicchlorid and chlorin, disconnect mg one of such bodies, removing thegases.

therefrom, removing chlorid from such gases and returning the residualgases to the process. y Y

25. The method of de-t-inning whichconsists in treating separate bodiesof tinned material with gaseous chlorin, disconnecting one of suchbodies, removing the gases therefrom, bringing the gases thus obtainedinto:

contact with a solven't for the chlorid of'tin L and chlorin. r

26.; The method of de-tinning which .consists in re-actingupon a body ofraw material while in its dry state with a mixture of gaseous stannicchloridand chlorin and conducting such gases to and from the reactionchamber at an elevated temperature,

27. The method ofdetinnin'g which consists in re-acting upon a body ofraw material while in its dry state with a mixture of gase ous stannicchlorid and chlorin and conducting such gases to and from the reactionchamber-at a temperature abovethe congealing point of stannic chloridhydrate.

2%. A method of detinning which consists,

in subjecting the raw material to the persist- I cut action of a mixtureof gaseous stannic chlorid and chlorin and afterwards treating same-withheated air.

29. The methodof detinning which con-v sists in subjecting the rawmaterial to the persistent action of a mixture of gaseous st'annicchlorid and chlorin andaft-erwards' v treating same with heated air andbringlng the resultinggases into contact with a suitable solvent. 7 I

30. The method of detinning whleh con: sistsin subjecting the rawmaterial "tb thev persistent action of a mixture of gaseous which con:

stannic. chlorid and chlorin, cutting ofi ,the

supplyand bringing the material to a higher than reacting temperaturewhile still connecterl to a receiver for stannic chlorid.

31. The method of cletinning which consists in subjecting the rawmaterial to.-the persistent action of a mixture of gaseous stannicchlorid and chlorin, cutting off the supply and bringing the material toa higher than re-actin temperature and supplying an inert gas to thematerial.

32. The method of cletinning and producing stannic chlorid whichconsists in treating the masses to be cletinned with chlorin and raisingand lowering the temperature of the mass during de-tinning by means outof contact therewith.

33. The method of detinm'ng which con sists in first refrigeratinggaseous chlorin for drying or rendering same anhydrous, raising thetemperature and then subjecting the raw material to action of the lrychlorin so treated.

34. The method of de-tinning and producing stannic chlorid whichconsists in treating the masses to be tie-tinned with chlorin whilecontrolling the temperature, finishing at a higher temperature than thatused at the start such heat being furnished by extraneous means.

In testimony whereof I have hereunto set my hand in presence of twosubscribing wit- IIGSSGS.

ELMER A. SPERRY. Witnesses:

MARGARET HIOKEY, ANNA T. BURT.

